This invention relates to a photographic film assemblage.
2. Description of the Prior Art
The present invention relates to a photographic film assemblage and more particularly to one which comprises a plurality of individual elements including film units and a dark slide stacked within a film cassette with the dark slide located (1) between an adjacent film unit and an exposure opening in the film cassette, and (2) in alignment with ingress and egress openings located in opposite walls of the film cassette. During insertion of the film assemblage into a film chamber of a camera, camera back, or other such apparatus, a film advancing member of the apparatus is adapted to enter the film cassette's ingress and engage a trailing edge of the dark slide. Further insertion of the film assemblage results in the dark slide being automatically moved, in the opposite direction, out of the film cassette via the egress thus preparing the underlying film unit for its photographic exposure. The film cassette includes means for preventing premature withdrawal of the film cassette during such insertion into the film chamber thereby obviating the exposure of a film unit to ambient light.
The broad concept of automatically removing a dark slide from a film cassette is well known as evidenced by U.S. Pat. No. 3,750,551. This patent shows a relatively expensive and elaborate circuit and film advancing apparatus for removing the dark slide from the cassette in response to the movement of the camera's loading door into its closed position.
A more basic arrangement for moving a dark slide from a film cassette in response to moving the film cassette further into a camera's film chamber is shown in U.S. Pat. No. 3,868,709. However, in this arrangement the dark slide is only partially removed from the film cassette in response to the continued movement or insertion of the cassette into the film chamber. A pair of driven rollers are located in the path of movement of the dark slide and are adapted to receive the dark slide and continue its movement towards the exterior of the camera.